Methods for processing crushed solids with a liquid within a vessel

ABSTRACT

A method is provided in which solids, such as run-of-mine ore, are crushed and reacted with a liquid within a mass flow reactor as a substantially continuous process. The reaction can include dissolving at least one material out of the crushed solids and into solution with the liquid. Solid and liquid materials migrate through and are extracted from the mass flow reactor substantially under the influence of gravity alone and without the use of other relevant driving means or forces. The respective flows of solid and liquid materials through the mass flow reactor can be controlled so as to maintain generally constant levels of each therein. At least some of the reaction can occur under a predetermined hydrostatic head of the liquid. Further processing of the solid and liquid materials can be performed, including isolation of at least one material of interest extracted from the crushed solids.

BACKGROUND

Many applications are known wherein a liquid is reacted with aparticulated or crushed solid (“solids”) to enhance one or the other ofthe liquid or the solids (or both) for commercial benefit. One commonapplication is to react a liquid “lixiviant” with a solid to extract asoluble compound from the solid by way of percolating or washing thesolid with the liquid. (Accordingly, a “lixiviant” is a liquid used forthis purpose.) This process is commonly described as “leaching”, and isknown to various fields of endeavor. Typical examples include extractingvaluable metals from ores containing the metals by contacting the oreswith a lixiviant. The extracted metals will then be in solution with thelixiviant, and can be later removed from the lixiviant by known chemicalprocesses, such as chemical precipitation, to render a relatively pureform of the extracted metals, or a form that can be subsequentlyprocessed to render a relatively pure form of the extracted metals. Oneexample is to wash ore containing gold with a lixiviant containingcyanide to remove the gold from the ore. Other examples include washingoil shales with a solvent to extract petroleum from the shales, andwashing coal with a sulfur-extracting liquid to remove sulfur from thecoal. Yet another example includes contacting contaminated soil with aliquid-borne biological agent (or agents) to thereby decontaminate thesoil.

In all of these processes the volumes of solids to be treated aretypically considerable—on the order of tens to thousands of metric tonsper day. In the case of ore leaching (to remove valuable metals fromores containing the metals), the most common process is to pile the oreinto a “heap” on a leach pad, and then to introduce a lixiviant onto thetop of the heap. After the lixiviant has passed through the ore heap viagravity, the lixiviant is collected and processed to remove theextracted metals from the lixiviant. The spent ore is then discarded (asfor example by moving it to a spent ore pile), and new unprocessed oreis then placed on the leach pad, and the process repeated. Such leachpads often occupy areas covering many acres, and in some cases squaremiles. Due to the nature of the lixiviants used, and the metals beingextracted from the ores, leach pads are typically subject to significantenvironmental controls to reduce the possibility of potentialcontamination of soil surrounding the leach pad. Further, the oreleaching process via ore heaps and leach pads is a slow process. Commonleach times (i.e., the time between when the ore heap is initiallyformed and the lixiviant added to the ore heap, and the time when theore is considered “spent” and is removed from the leach pad) are on theorder of months. A six month leach time is not uncommon.

Other prior leaching methods and apparatus include: (1) batch tankleaching, (2) agitated vat leaching, (3) counter-current tank leaching,(4) permanent pad heap leaching (described briefly above), (5) re-usablepad heap leaching, and (6) bio-heap leaching. A common description foreach of these methods and apparatus is a “leach circuit”.

The specific shortcomings of the prior art are as follows.

For agitated vat leaching, the basic operational concept is to providean elevated contact rate of lixiviant and other additives to thesurfaces of the ore particles by (a) increasing the surfaces of the orewhich can be accessed by the lixiviant by grinding the ore to a particlesize that exposes the desired metal or mineral value, (b) vigorouslyagitating the ore and lixiviant so as to provide an elevated level ofcontact between unconsumed reaction agents, and (c) to readily removereaction outputs so as to maintain in majority concentration theunconsumed reaction agents.

The shortcomings of such a process include: (1) significant capital andoperational costs are associated with grinding the ore to a smallparticle size and vigorously agitating such a dense media as an oreslurry; (2) the processing time required for the desired recoverylevel—as short as 24 hours in the typical case—in conjunction with thesize limitations for a vessel which will afford reasonably good economicaccess of the agitation mechanical to the ore slurry, necessitates alarge number of containment vessels, which in turn necessitates a plantof commensurate size to contain and support the operation of thecontainment vessels, all of which requires significant capital and realestate to construct; (3) small particle sizes typically presentchallenges for disposal of spent ore since special impoundments aretypically required to de-water and stabilize it as permanent fill; (4)because of the relatively high capital and operating costs of such aleach process, the method is not economical for very low grade ores orores which require leach times in excess of 24 hours to achieve economicrecovery; (5) batch processing contains an inherent limitation in thatthere is wasted economic time between batch operations; and (6) becauseof the complexity of such a mechanically intensive process, design andconstruction times for the plant are relatively long (as compared toheap leaching, for example).

Heap leaching is an alternative to vat leaching and attempts to addressthe limitations of vat leaching with respect to low grade ores and oresthat require longer leach recovery times (e.g., using certain oxides andcertain sulfides). The basic operational concept of heap leaching is totrade-off leach recovery time for leach circuit processing size orvolume by (1) secondary or tertiary crushing of the ore instead ofgrinding to a fine grain size, (2) agglomerating the ore into relativelyuniform ore spheres to increase permeability of lixiviant and increasecontact effectiveness rather than agitating the ore, (3) stacking inbroad, relatively shallow piles on an impermeable layer instead ofbatching in expensive vessels, (4) sprinkling lixiviant on the ore,letting it trickle down under the action of gravity alone through theore, and collecting the pregnant solution from perforated pipes on thebottom of the heap rather than submerging the ore within a vat or tank,(5) blowing air into the heap (as in the case of bio-heap leaching), and(6) removing the ore continuously from the pad as in the case ofre-usable pads to make heap leaching a more continuous rather than abatch process.

Although heap leaching extends leaching technology to lower grade andharder-to-leach ores that are not economically done with vat leachingbecause of the implied processing volume required, heap leaching is lesseffective in extracting metals and the like from the ores, primarily dueto the absence of submersion of the ore in the lixiviant and agitationof the ore (as in agitated vat leaching). Of particular concern in theuse of a trickle-type application of lixiviant to a stack or pile of oreon a leach pad is channeling of the lixiviant, leaving significantportions of the leach pile without sufficient lixiviant to extract thetheoretical maximum recoverable metals using the heap.

Another inherent shortcoming of heap leach is the inability to controlenvironmental inputs such as temperature and oxygenation of the heap,which are critical factors in bio-heap leaching where the effectivenessof the bacteria is closely dependent on these variables.

Perhaps the greatest shortcoming of heap leaching is the capital andoperating costs associated with large volumes of material, especially inthe case of re-usable pads. Whereas in vat leaching the ore istransported in a slurry in pipe conduits, heap leaching, because of thelarge geometric extents of leach pads and complexity of stacking astable heap, has been performed almost exclusively with conventionaloverland conveyors and specialized spreading and reclaim conveyors,which imply high capital and operating costs as compared to the compactplant piping of vat leaching.

What is needed then is an economical, efficient method and/or apparatusto react solids and liquids with one another that achieves the benefitsto be derived from similar prior art apparatus and methods, but whichavoid the shortcomings and detriments individually associated therewith.

SUMMARY

One embodiment provides for a method of processing selected solids witha selected liquid, the method including the steps of providing a vessel,and crushing the solids to not less than a predetermined median particlesize. The crushed solids define, or are referred to herein, as crushedsolids. The method also includes the step of reacting the crushed solidswith the liquid within the vessel, such that a pregnant leach solutionand post-reaction solids are derived. At least some of the reacting ofthe aforementioned step occurs under conditions of a predeterminedhydrostatic head. The method further includes the step of migrating thepregnant leach solution and the post-reaction solids through the vesselsubstantially under the influence of gravity alone. Furthermore, themethod includes the step of extracting the pregnant leach solution andthe post reaction solids from the vessel.

Another embodiment provides for a method of processing a mine ore with alixiviant, the method including the step of providing a reaction vessel,wherein the vessel defines solids outlet openings and liquid outletopenings. The method also includes the step of crushing the mine ore tonot greater than a predetermined size, such that crushed ore is definedor derived. The method further includes the steps of reacting thecrushed ore with the lixiviant within the reaction vessel, thus derivinga pregnant leach solution and post-reaction solids, and extracting atleast some of the pregnant leach solution from the reaction vessel viathe liquid outlet openings substantially under the influence of gravityalone. The method includes extracting the post-reaction solids and atleast some of the pregnant leach solution from the reaction vessel viathe solids outlet openings substantially under the influence of gravityalone.

These and other aspects and embodiments will now be described in detailwith reference to the accompanying drawings, wherein:

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagrammatic view depicting a system that can be usedto perform a method according to one embodiment of the invention.

FIG. 2 is block diagrammatic view depicting details of the system ofFIG. 1.

FIG. 3A is flowchart depicting a method according to one embodiment ofthe invention.

FIG. 3B is a continuation of the flowchart of FIG. 3A.

FIG. 3C is a continuation of the flowchart of FIG. 3A.

DETAILED DESCRIPTION

In representative embodiments, the present teachings provide methods andapparatus for processing solids such as run-of-mine ore, in asubstantially continuous manner, so that one or more materials ofinterest can be extracted or isolated from the ore and further processedto a condition deliverable to the market place.

The following terms are defined as used herein:

Run-of-Mine Ore: Refers to matter comprising at least one material ofinterest that is to be extracted or separated from the balance of thematter. Run-of-mine ore (or, interchangeably, ore) is in essentially thesame condition as when it was removed from its natural or native sourceand, typically (but not exclusively), defines a substantially solid,chunk-like consistency and includes individual particles ofsubstantially varying size. Non-limiting examples of materials ofinterest within such ore include gold, silver, platinum group metals,gallium, lead, germanium, refractory metals, molybdenum, copper, zinc,uranium, cobalt, nickel, light metals, crude oil, caregens, rare earthelements, etc. Other ores, comprising other respective materials ofinterest, can also be used. Examples of a native source for run-of-mineore include, but are not limited to, a shaft mine, an open pit mine, astrip mine, etc.

Lixiviant: This refers to any of a number of chemical compounds,typically (but not necessarily) in a liquid state, which chemicallyreacts with run-of-mine ore so as to dissolve, or “leach”, one or morematerials out of the ore and into solution with the lixiviant.Non-limiting examples of lixiviant include an aqueous solution of acidor acids, an aqueous solution of acid or acids including an oxidizingagent, an aqueous solution of an alkali or alkali's, sulfuric acid, asolution including sulfuric acid, an aqueous solution of an alkali oralkalis' including an oxidizing agent, an aqueous solution of cyanideincluding an oxidizing agent, an aqueous solution of sodium or calciumhypochlorite, an aqueous solution of ferrous or ferric sulfate, anaqueous solution of ferrous or ferric sulfate including an oxidizingagent, an aqueous solution including a bacterial catalyst, an aqueoussolution of chlorine, an aqueous solution of hydrogen peroxide, asolution of ammonium thiosulfate, or an aqueous solution of air andsulfur dioxide and copper. Other suitable lixiviants can also be used.Various embodiments allow the use of a lixiviant (or lixiviants) oftypically greater concentration than those used in known heap leachingoperations. Furthermore, the concentration (and/or othercharacteristics) of a lixiviant can be controlled to tighter tolerances,if desired, during continuous mode operation of various embodiments, ascompared to known heap leaching operations.

Pregnant Leach Solution (PLS): This refers to a liquid comprising alixiviant—in some overall degree of chemical depletion orexpenditure—and one or more materials dissolved into solution therewith.Thus, pregnant leach solution typically results from a chemical reactionbetween a solid material, such as crushed run-of-mine ore, and apristine (new, fresh, or regenerated) lixiviant.

Post-Reaction Solids (PRS): This term refers to solids, typically in acrushed form, which have reacted with a lixiviant such that at leastsome amount of one or more materials are dissolved out of the solids. Asused herein, post-reaction solids are usually defined by crushedrun-of-mine ore that has reacted, to some degree, with a lixiviant asgenerally defined above. That is, such post-reaction solids aretypically defined by crushed ore matter that has been depleted, to someextent, of one or more materials previously present in its original(pre-reaction) condition. In some cases, post-reaction solids (PRS) willinclude some quantity (i.e., trace or residual amounts, etc.) ofpregnant leach solution (PLS) until and/or unless further treatments orprocessing steps are performed to remove (e.g., leach) such PLS borne bythe PRS.

Barren Solution: Generally, this term refers to lixiviant that has beenpreviously used within a leach process (i.e., was once a pregnant leachsolution) and has been processed or otherwise sufficiently reconstituted(i.e., recycled) so as to be useful in one or more embodiments.Non-limiting examples of such recycling steps can include removal of thematerials dissolved into solution with the PLS, reconstitution by gasinjection or addition of new acid, etc. In one example, a barrensolution is derived that can be used within a wash process in order toleach (soak, or free) another liquid out of a solid material, thusdefining an aqueous leachate. In another example, a barren solution isdefined by sufficiently recycling PLS so as to derive a lixiviant insubstantially new condition, and which can be used as such.

Turning now to FIG. 1, a block diagrammatic view depicts a system 100that can be used to perform one or more methods in accordance with thepresent teachings. While the system 100 depicts particular elements usedin accordance with one embodiment, it is to be understood that otherelements (not shown) can be used, and/or selected ones of those elementsshown FIG. 1 can be omitted, in accordance with other embodiments. Thus,the system 100 as depicted in FIG. 1, is but one of any number ofsystems that can be used in accordance with the present teachings.

The system 100 includes a supply of run-of-mine ore (ore) 102. Thesupply of ore 102 is typically piled in a covered or uncovered fashionto wait further processing, as described hereinafter.

The system 100 includes a crusher 104. The crusher 104 can be defined byany suitable means for crushing the ore 102 to a predetermined median(or, optionally, a mean, not-less-than, or not-to-exceed) size. In oneembodiment, the crusher 104 is defined by a jaw mill. In otherrespective embodiments, the crusher 104 is defined by a gyratory type orSAG mill. One of ordinary skill in the mining engineering arts is awareof numerous such crushers 104 for suitably crushing run-of-mine ore 102,in accordance with the specific type of ore 102 and/or the desiredmedian crushed size, and further elaboration is not required forpurposes herein. In any case, the crusher 104 is suitably selected andused to crush the run-of-mine ore 102, thus deriving (i.e., defining) asupply (or stream) of crushed solids (i.e., crushed ore) 106.

The system 100 includes a supply of lixiviant 108. The lixiviant 108 canbe defined by any suitable such lixiviant as defined above. Thelixiviant 108 is reacted with the crushed solids 106 in order to deriveone or more desired by-products (or effects) of the reaction such as,for example, a pregnant leach solution as defined above. For example,the lixiviant 108 can be suitably defined so as to react with thecrushed solids 106 such that gold is leached out of the crushed solids106 and into solution with the lixiviant 108. Other suitable lixiviants(i.e., liquids, etc.) 108 can also be used in accordance with theparticular type of crushed solids 106, the desired reaction to occurtherewith, etc. One of ordinary skill in the mining or chemical arts isaware of numerous such lixiviants 108 and their respective uses.

The system 100 of FIG. 1 also includes a slurry preparation tank 107.The slurry preparation tank (hereinafter, slurry prep tank) 107 can bedefined by a tank or box-like structure and can (optionally) be linedwith a hard coating or other suitable wear- or corrosion-resistantmaterial. In one embodiment, the slurry prep tank 107 is formed of steeland is lined with ceramic tile. Other embodiments of the slurry preptank 107, respectively formed from other suitable materials, can also bedefined and used. The slurry prep tank 107 is configured to receiverespectively controlled flows of the crushed ore 106 and the lixiviant108. In another embodiment (not shown), the slurry prep tank is alsoconfigured to receive a flow of a suitable flocculant. The slurry preptank 107 serves as a mixing chamber wherein the crushed ore 106 andlixiviant 108 (and flocculant, if used) are combined so as to define awetted material (or slurry) stream 109. In another embodiment of thesystem 100 (not shown), the slurry prep tank 107 is provided inconjunction with suitable piping or other material conduits so that flowof the crushed ore 106 can be optionally bypassed around the slurry preptank 107, while the flow of lixiviant 108 into the slurry prep tank iscurtailed. In yet another embodiment of the system 100 (not shown), theslurry prep tank 107 itself is omitted altogether.

The system 100 of FIG. 1 further includes a mass flow reactor 110. Themass flow reactor (MFR) 110 is also referred to herein as a vessel. Oneor more embodiments of mass flow reactor 110 suitable for use inaccordance with the present teachings is/are described in detail in U.S.patent application Ser. No. 10/447,801, titled METHODS AND APPARATUS FORPROCESSING MIXTURES OF LIQUIDS AND SOLIDS, as filed with the UnitedStates Patent and Trademark Office on May 29, 2003 and as incorporatedherein by reference in its entirety. The MFR 110 provides a vessel-likestructure within which the crushed solids 106 are reacted with thelixiviant 108. The crushed solids 106 and the lixiviant 108 can bereceived by the MFR 110 as respectively separate flows or as, or incombination with, the slurry stream 109, in accordance with the desiredmode of operation. As depicted in FIG. 1, it is presumed that reactionof the crushed solids 106 with the lixiviant 108 results in thederivation of post-reaction solids and pregnant leach solution,respectively. Other solids/liquids reactions, resulting in other solidand/or liquid by-products, can also be performed within the MFR 110.

The mass flow reactor 110 of FIG. 1 is configured to permit thepost-reaction solids and the pregnant leach solution to migrate throughthe MFR 110 and to be extracted there from substantially under theinfluence of gravity alone as a stream of post-reaction solids 112 and astream of pregnant leach solution 114, respectively. In this way, themass flow reactor 110 is distinct, for example, from an agitated vat orother type of ore-handling apparatus wherein driven paddles, augersand/or overall rotary motion are used (whether in conjunction withgravity or not) to forcibly induce ore (or other materials) to migratefrom an entry point to an exit point. Further operational aspects of themass flow reactor 110 will be discussed in detail hereinafter.

The system 100 of FIG. 1 includes a heat exchanger 115. The heatexchanger 115 receives the flow of PLS 114 from the mass flow reactor110. The heat exchanger 115 can be defined by any suitable form such as,for example, a plate-and-frame design, a serpentine tube design, amulti-tube single-pass design, etc. One of skill in the mechanicalengineering arts is aware of numerous heat exchanger 115 designs andtheir general use and further elaboration is not needed for purposehere. In one example, the heat exchanger 115 recovers heat from the PLS114 and routes it (interconnecting means not shown) for pre-heating thelixiviant 108 prior to introduction into the slurry prep tank 107 and/orthe MFR 110. In another example, such recovered heat is simply expelledto atmosphere via a suitably coupled cooling tower (not shown). In yetanother example, heat recovered from the heat exchanger 115 is used topre-heat water or another fluid for use in an electrical generationplant (not shown). In any of these examples, the pregnant leach solution114 is cooled to define a cooled PLS stream 117. In yet another example,the heat exchanger 115 is used to heat the PLS 114 to a temperaturegreater than that as it is received from MFR 110, prior to subsequentprocessing of the (heated) PLS 114. In such a case, the pregnant leachsolution is heated to define a heated PLS stream 117. In yet anotherembodiment of the system 100 (not shown), the heat exchanger 115 isoptionally bypassed or otherwise inoperative, or the heat exchanger 115itself is omitted altogether.

The system 100 includes pregnant leach solution process (PLS process)116. The PLS process 116 can be defined by any suitable process (orcombination of sub-processes) configured to receive the pregnant leachsolution stream 114 from the mass flow reactor 110, the cooled/heatedPLS stream 117 from the heat exchanger 115, and/or the PLS stream 134(described hereinafter) and to separate (i.e., extract) one or morematerials out of the residual pregnant leach solution. For example, asuitable PLS process 116 can be defined and used that causes gold toprecipitate out of solution with the remaining PLS liquid advancing tothe next stage. Non-limiting examples of process steps performed by thepregnant leach solution process 116 include any suitable one, orcombination of, heating or cooling, clarification, filtration, bulkprecipitation, pH modulation, solvent extraction, electrowinning,mercuric retorting, smelting, carbon column absorption, magneticseparation, cyclonic separation, etc. One of ordinary skill in themining engineering arts is aware of numerous, well-established methodsand materials for extracting particular materials out of pregnant leachsolution and specific definition and elaboration is not required.

In any case, the pregnant leach solution process 116 includes suitableprocess steps resulting in the extraction and isolation of one or moreminerals, metals, and/or other materials 118 in a condition suitable forprovision to the market, or further processing, if desired. Also, thePLS process 116 can be defined and operated so as to reconstitute (i.e.,recycle) the lixiviant within the PLS stream 114, 117 and/or 134, orsome fraction thereof, so that a renewed lixiviant stream (or supply)148 is derived. As depicted in FIG. 1, the renewed lixiviant 148 isrouted back to and combined with the supply or source of lixiviant 108.In another embodiment (not shown), the PLS process 116 is defined andoperated so as to derive a stream (or supply) of barren solution (notshown). Other embodiments of the pregnant leach solution process 116 canalso be defined and used.

The system 100 of FIG. 1 also includes a screen process 120. The screenprocess 120 can include any suitable mesh-like apparatus such as, forexample, a mesh conveyer belt, a vibratory screen assembly, etc. Othersuitable screen process 120 apparatus can also be used. The screenprocess (or screen) 120 is configured to receive and support thepost-reaction solids 112 such that post-reaction solids 112 of less thana predetermined size are separated from the balance of the PRS stream112. In one embodiment, the screen process 120 is configured so thatpost-reaction solids of less than ⅝ inch, defining fine solids (or“fines”), are separated from the balance of the post-reaction solids112. Other configurations for separating other sizes of post-reactionsolids 112 (i.e., solid matter) can also be defined and used. Thus,typical operation of the screen process 120 derives a stream (or supply)of relatively coarse post-reaction solids 122, and a stream (or supply)of fine solids 124.

As depicted in FIG. 1, the coarse solids 122 are routed onto otherprocessing 126, which can include any desirable step or combination ofsteps for handling the relatively coarse solids 122. Such otherprocessing 126 step or steps can include, for example, detoxificationand/or disposal of the coarse post-reaction solids 122, furtherextraction of another material of interest therefrom, processing and/ormarket preparation of “cleaned” coal or oil shale (e.g., coal or oilshale from which sulfur has been “washed” or leached within the MFR110), etc. One of skill in the mining arts is aware of numeroussubsequent steps that can be performed after screen separation of finesfrom coarse solids, and further elaboration is not needed for purposesherein.

The system 100 of FIG. 1 further includes a centrifuge process 128. Thecentrifuge process 128 includes any suitable apparatus configured toreceive the fine post-reaction solids (fines) 124 and to additionallyseparate pregnant leach solution (i.e., PLS 114) there from by way ofcentrifugal force (i.e., rapid rotation within a drum), thus deriving astream (or supply) of pregnant leach solution 130. The pregnant leachsolution 130 can be routed if needed to a clarifying process 132,described in detail hereinafter. Also, the centrifuge process 128derives a stream (or supply) of generally dried (i.e., “dewatered”)post-reaction solids 136. One of ordinary skill in the mining arts isaware of various suitable centrifuge processes and apparatus, andfurther elaboration is not required.

The system 100 also includes a barren solution (or water) wash 140.Typically, the barren solution wash 140 can be used to leach additionalPLS (i.e., PLS 114) out of the (dried, or “dewatered”) fine solids 136.For example, some fine solids 136 include surface geometry, absorptioncharacteristics, or other considerations that economically justify useof the barren solution wash 140 in order to recover additional materialof interest (i.e., cyanide complexed gold, etc.) therefrom. In oneembodiment, the barren solution wash is provided by way of a vesselsubstantially mechanically equivalent to the mass flow reactor 110.However defined and used, the barren solution (or water) wash 140derives a stream (or supply) of aqueous leachate 142 borne by the(dried) fine solids as they exit the barren solution wash 140. In asense, the fine solids 136 have been “rewetted” by way of soaking(leaching) within the barren solution wash 140 in the interest ofrecovering additional material of interest therefrom (e.g., dissolvedcopper, etc.). In some cases, the barren solution or water wash 140 isnot used at all.

The system 100 also includes another centrifuge 144. The centrifuge 144can be defined by any suitable apparatus configured to receive thestream of “rewetted” fine solids from the barren solution wash 140 andto separate the aqueous leachate 142 therefrom by way of centrifugalforce. In this way, the centrifuge 144 derives a stream (or supply) ofliquid aqueous leachate 146 and a stream (or supply) of re-dried (or“dewatered”) fine solids 145. As also depicted in FIG. 1, re-dried finessolids 145 are optionally routed onto other processing 138, which caninclude any desirable step or combination of steps for handling there-dried fines solids 145. Such other processing 138 step (or steps) caninclude, for example, detoxification and/or disposal of the re-driedfines 145, further extraction of another material of interest therefrom,cyclonic (or other) separation of different sizes (or classes) of finesmaterial 145, etc. One of skill in the mining arts is aware of numeroussubsequent steps that can be performed after centrifuge separation ofliquid from fines, and further elaboration is not needed for purposesherein.

The system 100 includes a clarifying process 132. The clarifying process132 can be defined by, or include, any suitable apparatus or processingstep (or steps), if any, as desired or required, to remove solids fromor otherwise handle the stream of pregnant leach solution 130 generatedby the centrifuge process 128, and/or the aqueous leachate 146 generatedby the centrifuge 144. For example, in a case where the PLS 130 contains5000 ppm solids, reacted lixiviant and material of interest therein(e.g., dissolved copper, etc.), the clarifying process 132 can besuitably defined to remove a substantial fraction of the solidstherefrom. In any case, the clarifying process 132 derives a stream (orsupply) of pregnant leach solution 134 to be routed on to the PLSprocess 116 described above. In another embodiment of the system 100(not shown), the clarifying process 132 is bypassed or omittedaltogether. In yet another embodiment (not shown), the clarify process132 can be suitably interconnected to the heat exchanger 115 so as to beheated or cooled thereby.

The system 100 of FIG. 1 depicts particular system elements (i.e.,process apparatus) coupled in particular cooperative relationships.However, it is to be understood that other systems (not shown) can alsobe defined and used in accordance with various correspondingembodiments. Further exemplary operation of the system 100 will bedescribed hereinafter. While the system 100 of FIG. 1 is described abovein terms of processing run-of-mine ore (i.e., 102), it is to beunderstood that another system (not shown), including a mass flowreactor (e.g., MFR 110, etc.), can also be defined and used fordecontaminating soil and the like. One of ordinary skill in the miningor industrial arts and/or geological sciences will recognize that theMFR 110 can provide a basis for any number of substantially continuousprocesses involving reactions between solid and liquid materials.

FIG. 2 is a block diagrammatic view depicting selected details of thesystem 100 of FIG. 1. As depicted in FIG. 2, the mass flow reactor(i.e., vessel) 110 is coupled to receive the stream of crushed solids(i.e., crushed ore) 106 directly—that is, the slurry prep tank 107 ofFIG. 1 is not included. Furthermore, the mass flow reactor 110 iscoupled in fluid communication with the supply of lixiviants 108. Asdepicted in FIG. 2, the MFR 110 receives the crushed solids 106 via atleast one point (or opening) 150 proximate an open top of the MFR 110.However, in another embodiment (not shown), the MFR 110 is configured toreceive the crushed solids 106 via at least one point (or opening)elevationally lower with respect to the MFR 110. It is to be understoodthat the system 100 is suitably equipped to regulate the flow of crushedsolids 106 into the mass flow reactor 110 over some predetermined range,including complete shut off (zero flow).

The mass flow reactor 110 is also configured to receive the lixiviant108 at a plurality of liquid entry points (or openings) 152elevationally distributed within the MFR 110. While not specificallydepicted in FIG. 2, it is understood that the mass flow reactor 110 issuitably equipped (e.g., via valves, pressure regulators, electronicand/or pneumatic controls, etc.) so as to throttle, or regulate, theflow of lixiviant 108 (i.e., liquid) through each of the liquid entrypoints 152 over some predetermined range, including complete shut off.The flow of lixiviant 108 can be independently controlled through eachliquid entry point 152, suitably ganged so as to throttle each liquidentry point 152 flow in unison with the others, etc.

The MFR 110 is also configured to permit the extraction of post-reactionsolids 112 from one or more solids exit points (or openings) 154.Typically, at least one such solids exit point 154 is coincident with,or substantially proximate to, a bottom center “B” as defined by themass flow reactor 110. Other respective suitable locations defined bythe MFR 110 can also be used for locating the solids exits points 154.In any event, the mass flow reactor 110 is suitably equipped so as tothrottle the flow of post-reaction solids 112 through each of the solidsexit points 154 over some predetermined range, including complete shutoff. The flow of post-reaction solids 112 can be independentlycontrolled through each solids exit point 154, coupled (ganged) so as tothrottle each exit point 156 flow in unison with the others, etc.

The MFR 110 is further configured to permit the extraction of pregnantleach solution 114 at a plurality of liquid exit points (or openings)156 elevationally distributed within the MFR 110. It is to be understoodthat the mass flow reactor 110 is also suitably equipped so as tothrottle (regulate) the flow of lixiviant pregnant leach solution 114(i.e., liquid) through each of the liquid exit points 156 over somepredetermined range, including complete shut off. The flow of PLS 114can be independently controlled though each liquid exit point 156,ganged such that each liquid exit point 156 flow is throttled in unisonwith the others, etc.

It is important to note that the mass flow reactor 110 as depicted byFIG. 2 is configured such that post-reaction solids 112 and pregnantleach solution 114 (as well as, to some respective extents, crushedsolids 106 and lixiviant 108) are induced to migrate (or flow) thoroughthe MFR 110 substantially under the influence of gravity alone, in theprevailing direction indicated by the arrow “G”. It is to be furtherunderstood, of course, that post-reaction solids 112 and pregnant leachsolution 114 also migrate toward their respective solids exit points 154and liquid exit points 156, in various directions which deviate from theprevailing direction “G” in order for material (e.g., PRS 112 and PLS114) extraction from the MFR 110 to be performed. However, suchextraction of the post-reaction solids 112 and the pregnant leachsolution 114 is also performed substantially under the influence ofgravity alone. As used herein, “substantially under the influence ofgravity alone” refers to migration or motion of respective materialsthrough the mass flow reactor 110 without the use of other mechanicaldriving means or influences—for example, the mass flow reactor 110 isdevoid of any driven paddles or augers, downward and/or upward liquidjetting, or vibration, shaking, rocking or rotation of the MFR 110, andwherein gravity accounts for not less than ninety percent of the overallmigration-inducing force when the mass flow reactor 110 is operated witha gaseous pressure (other than ambient atmospheric) present over theliquid and/or solids materials being processed within the MFR 110 (e.g.,see location “U” in FIG. 2). This makes operation of the mass flowreactor 110 distinct from other types of vessels or processing conduitsknown in mining or the related arts.

The mass flow reactor 110 of FIG. 2 is also configured so as to definean internal cavity of volume “V”, and a maximum possible (or working)depth “L” of liquid there in. In this way, it is possible to establish apredetermined hydrostatic head gradient by providing and/or maintainingthe corresponding depth “L” of liquid (i.e., lixiviant 108 and PLS 114)within the MFR 110. In one exemplary embodiment, the MFR 110 isconfigured such that a stratum corresponding to a hydrostatic head “H”in excess of 65 feet of the liquid is present, and can be maintained,within the mass flow reactor 110. Other configurations of MFR 110corresponding to other (potential) magnitudes of hydrostatic head canalso be used. In any case, the mass flow reactor 110 can be suitablyconfigured to provide a zone (or stratum) where at least some of thereaction of the crushed solids 106 with the lixiviant 108 can take placeunder a predetermined hydrostatic head “H” of the liquid. As depicted inFIG. 2, the MFR 110 can be generally open to ambient atmosphericpressure at an elevationally upper end “U”. In another embodiment (notshown), the MFR 110 is configured such that a non-atmospheric pressure(i.e., a relative vacuum or over-atmospheric pressure) is present overthe liquid within the MFR 110, wherein such pressure—be it atmosphericor not—can be provided by way of any suitably selected gas (e.g., air,O₂, N₂, NO_(x), CO₂, etc.).

As depicted in FIG. 2, the mass flow reactor 110 is coupled in fluidcommunication with a supply of gas 158. The MFR 110 receives the gas 158by way of at least one gas entry point (or opening) 160. Such gas entrypoint or points 160 can be selectively located and/or distributed withinthe MFR 110 as desired or required. Non-limiting examples of the gas 158include an oxygen/air mixture, a sulfur dioxide/air mixture, air, pureoxygen, a gaseous oxidizing agent, or any of these or another suitablegas or gasses dissolved in a liquid or lixiviant that is injected intothe reactor 110 via entry port(s) 160, etc. Other suitable gases 158 canalso be defined and used in. For example, the gas 158 can be anoxygen/air mixture of predetermined ratio that is provided to the MFR110 for purpose of oxidizing sulfur compounds present within orliberated from the crushed solids 106 so that such oxidized sulfurcompounds are more readily handled at some subsequent process (notshown) external to the mass flow reactor 110. Furthermore, the mass flowreactor 110 in the upper end “U” (or area proximate thereto) can besuitably equipped with ducting or piping, fume collection hoods, fans,etc. (not shown), so that gases (e.g., the gas 158, a gaseous by-productor by-products of reaction, etc.) can be captured/collected and routedaway from the MFR 110 for containment, processing, etc. In any case, oneof ordinary skill in the mining arts is aware of numerous processes inwhich one or more gases can be injected into a reaction zone for one ormore purposes, and further elaboration is not required.

The mass flow reactor 110 of FIG. 2 can also be coupled to a supply offlocculant 170 that can be controllably introduced into the MFR 110 atone or more flocculant entry points (or openings) 172. The flocculant170 can be defined by any suitable agent used to cause relatively fineparticles of the crushed solids 106 to adhere to one another, thusdefining a plurality of larger solids entities. In an alternativeembodiment, the flocculant 170 is defined by any suitable agent thatcauses such fine particles of the crushed solids 106 to adhere torelatively larger particles (or chunks) of the crushed solids 106(agglomeration). In this way, an overall permeability of the crushedsolids 106 with respect to the lixiviant (liquid) 108 within the MFR 110can be suitably affected so as to increase contact between the two. Inany case, the flocculant 170 can be provided to the MFR 110 when suchflocculation or agglomeration is desired. One of ordinary skill in themining arts is familiar with the selection and use of flocculants 170 asapplied to processing ore “fines”, and further elaboration is notrequired here.

In another embodiment (not shown), a supply of inert solids is providedand selectively used so as to affect and/or stabilize one or morephysical characteristics during reaction of solids with liquid(s) withina mass flow reactor (e.g., the MFR 110, etc.) such as, for example,increasing or decreasing heat conductivity, increasing or decreasingheat absorption, increasing or decreasing heat capacity, etc.Non-limiting examples of such inert solids (not shown) include steelspheres, etc.

FIG. 3A is flowchart 200 depicting a method in accordance with oneembodiment of the present teachings. The method of the flowchart 200 isdescribed hereinafter in reference to system 100 of FIGS. 1 and 2 in theinterest of understanding. However, it is to be understood that themethod of the flowchart 200 can also be performed using other systemsand/or elements (not shown) within the scope of the present teachings.While the flowchart 200 depicts particular method steps and order ofexecution, it is to be understood that other embodiments that includeother respective steps and/or orders of execution can also be used.Thus, the method of the flowchart 200 is exemplary of any number ofother such methods within the present scope.

In step 202 (FIG. 3A), run-of-mine ore is crushed to a suitable mediansize. For purposes of example, it is assumed that gold-bearing,run-of-mine ore 102 (FIG. 1) is crushed using a suitable crusher 104 soas to derive (define) crushed solids (i.e., crushed ore) 106 having amedian size of approximately 0.375 inches in diameter. Other mediansizes and/or sizing schemes for the crushed solids 106 can also be used.

In step 204 (FIG. 3A), crushed solids 106 (FIG. 2) are provided directlyinto the mass flow reactor 110 by way of solids entry point 150 so as tofill the MFR 110 to a predetermined operating depth (i.e., vertical piledimension) “S”. Thus, the slurry prep tank 107 (FIG. 1) is assumed to bebypassed or otherwise unused. For purposes of the ongoing example, it isassumed that the MFR 110 is filed with crushed solids 106 to a depth “S”of eighty feet. Other operating depths of the crushed solids 106 withinthe MFR 110 can also be used. It is further assumed that the cavityvolume “V” defined by the mass flow reactor 110 is such that 82,700 tonsof crushed solids 106 are present when the exemplary depth “S” of eightyfeet is achieved. It is important to note that at this time, no materialis being extracted from the MFR 110. Once the desired depth “S” ofcrushed solids 106 is established in the MFR 110, the flow thereof isceased at least for the time being. Also at this time or anytime whilefilling, any initial amount of flocculant 160 that is desired can beprovided into the MFR 110.

In step 206 (FIG. 3A), a predetermined liquid lixiviant 108 (FIG. 2) isprovided into the mass flow reactor 110 by way of controlled flowthrough one or more of the liquid entry points 152. For purposes ofexample, it is assumed that a predetermined operating depth “L” ofninety feet of the lixiviant 108 (i.e., liquid) is established in theMFR 110. Other operating depths “L” can also be used. It is furtherassumed that the lixiviant 108 is defined by an aqueous solutionincluding cyanide. As in step 204 (FIG. 3A) above, no material is beingextracted from the MFR 110 (FIG. 2) at this time. Once the desiredliquid depth “L” of lixiviant 108 is established in the MFR 110, theflow thereof is ceased for the time being.

In step 208 (FIG. 3A), the crushed solids 106 (FIG. 2) are reacted withthe lixiviant 108 within the MFR 110 for a predetermined period of time,or dwell, so as to permit at least one material of interest to bedissolved out of the crushed solids 106 and into solution with thelixiviant 108. Thus, the derivation of post-reaction solids 112 andpregnant leach solution 114 is underway. Also, if desired or required,the gas 158 can be controllably introduced into the mass flow reactor110. This dwell time (i.e., period of reaction without any extraction ofpost-reactions solids 112 or pregnant leach solution 114) can beperformed for any predetermined period of time such as, for purposes ofexample, five hours, etc.

In step 210 (FIG. 3A), the post-reaction solids 112 (FIG. 2) and thepregnant leach solution 114 (as well as substantially not-yet-reactedlixiviant 108 and crushed solids 106) begin to migrate through the massflow reactor 110 in the prevailing direction “G”, by way of gravityalone. In this initial instance, such migration is generally due tosettling of material due to the liquid-bath conditions present in theMFR 110.

In step 212 (FIG. 3A), which in fact can occur just prior to, or almostsimultaneously with, step 210 above, the extraction of post-reactionsolids 112 (FIG. 2) via one or more of the solids exits points 154begins. The extraction of pregnant leach solution 114 by way of one ormore of the liquid exit points 156 is also begun. The extraction of thepost-reaction solids 112 is generally performed in a controlled fashionso that the volumetric (or mass) flow of the post-reaction solids 112follows a predetermined pattern or scheme, defining a solids extractionflow rate. In turn, the extraction of pregnant leach solution 114 isalso performed in a predetermined controlled-flow manner, defining aliquid extraction flow rate. Such solids and liquids extraction flowrates can be, respectively, substantially constant, increase or decreaselinearly or non-linearly over time, etc. In short, any desired flow ratecharacteristic can be independently employed in regard to the extractionof post-reaction solids 112, and any desired flow rate characteristiccan be employed, up to the maximum permeability rate, in regard to theextraction of pregnant leach solution 114. In any case, the extractionof PRS 112 and PLS 114 is performed substantially under the influence ofgravity alone as previously described above.

Also in step 212 (FIG. 3A), the introduction (or addition) of crushedsolids 106 (FIG. 2) into the MFR 110 is performed at a rate inaccordance with the extraction of post-reaction solids 112. Furthermore,lixiviant 108 is added to the MFR 110 at a rate corresponding to theextraction of pregnant leach solution 114. Thus, at this time, crushedsolids 106 are added to, and post-reaction solids 112 are extractedfrom, the mass flow reactor 110 in a simultaneous fashion such that a“mass flow” or migration (substantially under the influence of gravityalone) of solid material through the MFR 110 is established andmaintained for a predetermined period of time. For purposes of theongoing example, this simultaneous flow of crushed solids 106 andpost-reaction solids 112 is maintained for a period of at least of atleast 3 days. Typically, the crushed solids 106 and the post-reactionsolids 112 are extracted at substantially equal and/or constant rates,such that the predetermined depth “S” of solids (e.g., eighty feet,etc.) within the MFR 110 is generally maintained constant during this“simultaneous flow” period. Furthermore, lixiviant 108 is added to, andpregnant leach solution 114 (as well as any trace and/or incidentalamount of PLS borne by the PRS 112) is extracted from, the MFR 110 in asimultaneous fashion, such that a gravity-driven mass flow or migrationof liquid material through the MFR 110 is established and maintained fora period of time. For purposes of the ongoing example, this simultaneousflow of lixiviant 108 and pregnant leach solution 114 (as well as anyresidual amount of PLS borne by the PRS 112) is maintained for a periodof at least 3 days. Generally, the respective flow rates of thelixiviant 108 and the pregnant leach solution 114 are controlled atsubstantially equal and/or constant rates, such that the predeterminedliquid depth “L” (e.g., ninety feet, etc.) is maintained essentiallyconstant within the MFR 110 during the time of simultaneous flows.

It is important to note that the respectively controlled flow rates ofsolids (i.e., crushed solids 106 and PRS 112) and liquids (i.e.,lixiviant 108 and PLS 114) through the mass flow reactor 110 results inthe reacting, or processing, of ore or other solid materials in a mannerthat is substantially continuous—rather than batch-like—in overallprocess operation. This means that once the desired depths (i.e.,quantities) of solids “S” and liquid “L” are established in the MFR 110(e.g., as in steps 204 and 206 above), such respective depths (or massquantities, etc.) can be maintained essentially constant within the massflow reactor 110, if desired, by way of appropriate solids and liquidflow control in to and out of (that is, through) the MFR 110. Onceestablished, such continuous processing can be perpetuated foressentially any predetermined period of time (hours, days, weeks,months, etc.).

In step 214 (FIG. 3B), the post-reaction solids 112 (FIG. 1) are routedto a screen process 120. Therein, post-reaction solids 112 of less thana predetermined size are separated from the balance of the post-reactionsolids 112, thus defining a stream (or supply) of relatively coarsepost-reaction solids 122, and a stream (or supply) of finepost-reactions solids (or “fines”) 124. For purposes of example, it isassumed that the screen process 120 is defined and provided such thatthe fines 124 are comprised of individual particles less thanfive-eights inch in size. Other sizing (or classifying) schemes can alsobe used in separating fines 124 from coarse post-reaction solids 122.The coarse post-reaction solids 122 (FIG. 1) are then routed to suitableother processing 126 such as, for example, detoxification, disposal,heaping for later processing, etc.

In step 216 (FIG. 3B), the stream of fine post-reactions solids 124(FIG. 1) are received by a centrifuge process 128 where additionalpregnant leach solution (i.e., PLS 114) is extracted from the fines 124resulting in a stream (or supply) of pregnant leach solution 130. Inanother embodiment, (not shown), other equipment such as filters couldbe used instead of the centrifuge process 128. Fine post-reaction solidsexit the centrifuge process 128 and define a stream (or supply) of driedfines 136. While such are referred to as “dried”, it is to be understoodthat relatively small quantities of PLS 114 may still be present on, orabsorbed within, the dried fines 136. This aspect of the dried fines 136will be considered in further detail below.

In step 218 (FIG. 3B), the stream of pregnant leach solution 130(FIG. 1) is received by a clarifying process 132. The clarifying process132 removes solids from the PLS 130, by a gravity type clarifier, acyclonic type clarifier, by filters, or by any suitable known means, soas to derive a relatively low-solids stream (or supply) of pregnantleach solution 134. In this way, subsequent PLS 134 processing can beperformed with greater efficiency and/or efficacy as most of the solidsin the solution have been removed. In some embodiments, the clarifyingprocess 132 is omitted altogether, and the stream (or supply) of PLS 130directly defines the stream (or supply) of PLS 134 by way of, forexample, carbon columns treating dilute gold solutions.

In step 220 (FIG. 3B), the dried fines 136 (FIG. 1) are (optionally)routed to a barren solution (or water) wash 140. The barren solutionwash 140 is essentially a barren solution filled vessel in which thedried fines 136 are soaked for some period of time so as to furtherextract (i.e., leach) relatively small or trace amounts of pregnantleach solution (i.e., PLS 114) from the dried fines 136. Typically, thebarren solution wash 140 is used only when the material of interest(i.e., gold, platinum, etc.) dissolved into the pregnant leach solution(i.e., PLS 114) is of sufficient value to economically warrant suchextra processing. When used, the barren solution wash 140 derives astream (or supply) of aqueous leachate 142 borne by the “rewetted” finesolids. For purposes of ongoing example, it is assumed that at leastsome of the dried fines 136 are routed to the barren solution wash 140,where additional gold-bearing pregnant leach solution 114 is leached outof the dried fines 136 and into solution with the barren solution, thusdefining the aqueous leachate 142. It is also assumed that the finesbearing the aqueous leachate 142 are routed to other processing 138,where the aqueous leachate 142 is separated from the fines (e.g., by wayof centrifugal separation 144, a filter arrangement (not shown), etc.)and thereafter combined with the PLS stream 134 for additionalprocessing at step 222 below. In turn, it is further assumed that anynon-washed fine solids 136 are sent to respective other processing 138and are discarded, etc. In those embodiments (not shown in FIG. 3B)where the barren solution wash 140 is not used, the dried fines 136 aresimply routed to other processing 138 for detoxification, disposal,etc., as desired.

In step 222 (FIG. 3C), the respective streams (or supplies) of pregnantleach solution 114 (FIG. 1) and 134 are received at a pregnant leachsolution process 116. Thus, with respect to the PLS stream 114, the heatexchanger 115 (FIG. 1) is assumed to be bypassed or otherwise unused.Therein, any suitable process step or combination of steps and/orapparatus is/are used to extract at least a majority of the material ofinterest from the aggregate pregnant leach solution (114 and 134 of FIG.1). For purposes of ongoing example, it is assumed that dissolved goldis recovered from the aggregate PLS by way of adsorption, elution,electrowinning and retorting—processes known to one of ordinary skill inthe mining engineering arts. The recovered material of interest (e.g.,gold, etc.) is then sent on to step 224 (FIG. 3C) below. The residualliquid of processing the pregnant leach solution (114 and 134 of FIG. 1)is assumed to be processed as desired by way of regeneration,destruction, containment and disposal, etc.

In step 224 (FIG. 3C), the recovered material of interest from step 222above is finally processed as needed so as to be delivered to the marketplace. For purposes of example, it is assumed that retorted gold issmelted by known techniques to produce gold bullion. Other process stepscan also be employed, as needed or desired, in accordance with the goalat hand. In this way, the steps 222 and/or 224 are typically performedso as to isolate at least one material of interest, as originallypresent in the run-of-mine ore 102 (FIG. 1), in a form that can beprovided to (i.e., sold within) the market. At this point, the exemplarymethod of the flowchart 200 is presumed to be completely described.

In the interest of understanding, at least some of the characteristicsand advantages of the present teachings are summarized as follows:

a) The reaction of crushed solids with lixiviant (or other liquid) canbe performed within a vessel, otherwise referred to as a mass flowreactor, as a substantially continuous process;

b) Solid and liquid materials migrate through, and are extracted from, amass flow reactor substantially under the influence of gravity alone andwithout the use of other relevant mechanical means or forces such as,for example, driven paddles, augers, downward and/or upward liquidjetting, or vibrating, rocking, shaking, and/or rotating the mass flowreactor, and wherein gravity is not less than ninety percent of themigration-inducing force when gaseous pressure is present over thematerials within the mass flow reactor;

c) At least some of the reaction of crushed solids with liquid within amass flow reactor can be performed under conditions of a predeterminedhydrostatic head of the liquid;

d) A flocculant can be used, if desired, to affect the permeability ofcrushed solids with respect to liquid within a mass flow reactor. Inthis way, liquid-on-solid contact, and the corresponding reactionbetween solids and liquids, can be suitably increased;

e) A gas can be injected into a mass flow reactor so as to oxidize orotherwise chemically affect compounds present during the reaction ofcrushed solids with liquid.

f) One or more physical and/or chemical variables can be suitablycontrolled within the mass flow reactor during processing, by anyrespectively suitable known means. Non-limiting examples of suchvariables include pH, Eh (i.e., electron potential in solution),temperature, viscosity, the concentration of a gas, the concentration ofa liquid, etc.

g) A suitable inert solid can be used, if desired, to affect—increase,decrease or stabilize—one or more characteristics within a mass flowreactor during a reaction between solids and a liquid or liquids.Non-limiting examples of such characteristics include heat conductivity,heat absorption, etc.

It is anticipated that the invention will be embodied in other specificforms, not specifically described, that do not depart from its spirit oressential characteristics. The described embodiments are to beconsidered in all respects only as illustrative and not restrictive, thescope of the invention being defined by the appended claims andequivalents thereof.

1. A method of processing solids with a liquid, comprising: providing avessel; crushing the solids to not less than a predetermined medianparticle size, thus defining crushed solids; reacting the crushed solidswith the liquid within the vessel, thus deriving a pregnant leachsolution and post-reaction solids, wherein at least some of the reactingoccurs under a predetermined hydrostatic head; migrating the pregnantleach solution and the post-reaction solids through the vesselsubstantially under the influence of gravity alone; and extracting thepregnant leach solution and the post-reaction solids from the vessel. 2.The method of claim 1, wherein the crushed solids define a permeabilitywith respect to the liquid within the vessel, the method furthercomprising: controlling the permeability by way of at least one of:chemically flocculating fine particles of the crushed solids to formlarger particles of the crushed solids within the vessel; agglomeratingfine particles of the crushed solids to larger particles of the crushedsolids prior to the reacting within the vessel; or removing fineparticles of the crushed solids by way of at least one of dry screening,wet screening, or cyclonic separation of the crushed solids prior to thereacting within the vessel.
 3. The method of claim 1, wherein thepredetermined hydrostatic head is not less than 65 feet of the liquid.4. The method of claim 1, wherein the reacting includes leaching atleast one material out of the crushed solids and into solution with theliquid, thus deriving the pregnant leach solution and the post-reactionsolids.
 5. The method of claim 4, wherein the at least one materialleached out of the crushed solids includes gold, silver, a platinumgroup metal, gallium, germanium, lead, copper, zinc, uranium, cobalt,nickel, a refractory metal, molybdenum, a light metal, sulfur, crudeoil, caregens, or a rare earth element.
 6. The method of claim 1,wherein the liquid includes an aqueous solution of acid or acids, anaqueous solution of acid or acids including an oxidizing agent, sulfuricacid, a solution including sulfuric acid, an aqueous solution of analkali or alkali's, an aqueous solution of an alkali or alkalisincluding an oxidizing agent, an aqueous solution of cyanide includingan oxidizing agent, an aqueous solution of sodium or calciumhypochlorite, an aqueous solution of ferrous or ferric sulfate, anaqueous solution of ferrous or ferric sulfate including an oxidizingagent, an aqueous solution including a bacterial catalyst, an aqueoussolution of chlorine, an aqueous solution of hydrogen peroxide, asolution of ammonium thiosulfate, or an aqueous solution of air andsulfur dioxide and copper.
 7. The method of claim 1, wherein the solidsinclude one of gold-bearing ore, silver-bearing ore, ore bearing atleast one platinum group metal, ore bearing rare earth elements, orebearing gallium, ore bearing germanium, ore bearing light metals, orebearing copper, ore bearing zinc, ore bearing molybdenum, ore bearinglead, ore bearing uranium, ore bearing cobalt, ore bearing nickel, orebearing refractory metal, contaminated soil, solids containing coal,solids containing oil sands, and solids containing oil shales.
 8. Themethod of claim 1, and further comprising adding the liquid into thevessel at a first flow rate, wherein the pregnant leach solution isextracted from the vessel at a second flow rate, and wherein the addingthe liquid and the extracting the pregnant leach solution are performedsimultaneously for a predetermined period of time.
 9. The method ofclaim 8, wherein the first and second flow rates are at least one ofessentially equal or essentially constant for the predetermined periodof time.
 10. The method of claim 8, wherein the predetermined period oftime is not less than 3 hours.
 11. The method of claim 1, and furthercomprising adding the crushed solids into the vessel at a first flowrate, wherein the post-reaction solids are extracted from the vessel ata second flow rate, and wherein the adding the crushed solids and theextracting the post-reaction solids are performed simultaneously for apredetermined period of time.
 12. The method of claim 11, wherein thefirst and second flow rates are at least one of essentially equal oressentially constant for at least the predetermined period of time. 13.The method of claim 11, wherein the predetermined period of time is notless than 3 hours.
 14. The method of claim 1, wherein the post-reactionsolids are extracted from the vessel proximate a bottom of the vessel.15. The method of claim 1, wherein the post-reaction solids areextracted from the vessel substantially under the influence of gravityalone.
 16. The method of claim 1, wherein the pregnant leach solution isextracted from the vessel substantially under the influence of gravityalone.
 17. The method of claim 1, and further comprising separating atleast some of the post-reaction solids into at least two distinctgroups, wherein each group corresponds to a predetermined medianparticle size of post-reaction solid.
 18. The method of claim 1, andfurther comprising removing pregnant leach solution from at least someof the post-reaction solids.
 19. The method of claim 18, includingcentrifuging at least some of the post-reaction solids to remove atleast some of the pregnant leach solution.
 20. The method of claim 18,including passing at least some of the post-reaction solids along ascreen to remove at least some of the pregnant leach solution.
 21. Themethod of claim 18, including leaching at least some of thepost-reaction solids in a barren solution wash, thus deriving an aqueousleachate.
 22. The method of claim 21, wherein the vessel is a firstvessel, the method further comprising: providing a second vessel;performing the leaching of at least some of the post-reaction solids inthe barren solution wash within the second vessel, thus deriving theaqueous leachate and post-leaching solids; and extracting the aqueousleachate and the post-leaching solids from the second vessel.
 23. Themethod of claim 1, and further comprising extracting at least onematerial from the pregnant leach solution.
 24. The method of claim 23,wherein the at least one material includes gold, silver, a platinumgroup metal, gallium, germanium, molybdenum, lead, copper, zinc,uranium, cobalt, nickel, a refractory metal, a light metal, crude oil,sulfur, or a rare earth element.
 25. The method of claim 23, wherein theextracting includes at least one of using a solvent extraction ,chemical precipitation, or electrolytic precipitation.
 26. The method ofclaim 1, and further comprising controlling at least one of pH, Eh,temperature, a gas concentration, or a liquid concentration within thevessel during the reacting the crushed solids with the liquid.
 27. Themethod of claim 1, wherein the vessel is a first vessel and the liquidis a first liquid and the pregnant leach solution is a first leachsolution and the post-reaction solids are first post-reaction solids,the method further comprising: providing a second vessel; and reactingat least some of the post-reaction solids with a second liquid withinthe second vessel, thus deriving a second pregnant leach solution andsecond post-reaction solids.
 28. The method of claim 1, and furthercomprising injecting a gas into the vessel during at least some of thereacting the crushed solids with the liquid.
 29. The method of claim 28,wherein the gas is defined by an oxidizing gas.
 30. The method of claim1, wherein the crushed solids within the vessel define a permeabilitywith respect to the liquid, the method further comprising: providing atleast one essentially inert solid within the vessel during the reactingso as to increase the permeability of the crushed solids with respect tothe liquid.
 31. A method of processing mine ore with a lixiviant,comprising: providing a reaction vessel defining solids outlet openingsand liquid outlet openings; crushing the mine ore to not greater than apredetermined size, thus defining crushed ore; reacting the crushed orewith the lixiviant within the reaction vessel, thus deriving a pregnantleach solution and post-reaction solids; extracting at least some of thepregnant leach solution from the reaction vessel via the liquid outletopenings substantially under the influence of gravity alone; andextracting the post-reaction solids and at least some of the pregnantleach solution from the reaction vessel via the solids outlet openingssubstantially under the influence of gravity alone.
 32. The method ofclaim 31, wherein the predetermined size is such that at least 80percent of the crushed ore is not greater than 6 inches in size.
 33. Themethod of claim 31, and further comprising removing solids of less than0.15 millimeters from the crushed ore prior to the reacting the crushedore with the lixiviant within the reaction vessel, the removed solidsdefining fine solids.
 34. The method of claim 33, and further comprisingremoving at least one material from the fine solids by way of leachingthe fine solids.
 35. The method of claim 31, wherein: the reactingincludes dissolving at least one material out of the crushed ore andinto solution with the lixiviant, thus deriving the pregnant leachsolution; and the at least one material includes gold, silver, aplatinum group metal, gallium, lead, germanium, copper, molybdenum,zinc, uranium, cobalt, nickel, a refractory metal, a light metal,sulfur, crude oil, or a rare earth element.
 36. The method of claim 31,wherein the lixiviant includes an aqueous solution of acid or acids, anaqueous solution of acid or acids including an oxidizing agent, sulfuricacid, a solution including sulfuric acid, an aqueous solution of a baseor bases, an aqueous solution of a base or bases including an oxidizingagent, an aqueous solution of cyanide including an oxidizing agent, anaqueous solution of sodium or calcium hypochlorite, an aqueous solutionof ferrous or ferric sulfate, an aqueous solution of ferrous or ferricsulfate including an oxidizing agent, an aqueous solution including abacterial catalyst, an aqueous solution of chlorine, an aqueous solutionof hydrogen peroxide, a solution of ammonium thiosulfate, a lixiviantfor leaching uranium, or an aqueous solution of air and sulfur dioxideand copper.
 37. The method of claim 31, wherein the crushed ore includesgold-bearing ore, silver-bearing ore, ore bearing at least one platinumgroup metal, ore bearing rare earth elements, ore bearing gallium, orebearing germanium, ore bearing light metals, ore bearing copper, orebearing zinc, ore bearing molybdenum, ore bearing lead, ore bearinguranium, ore bearing cobalt, ore bearing nickel, ore bearing refractorymetals, solids containing coal, solids containing oil sands, or solidscontaining oil shales.
 38. The method of claim 31, and furthercomprising introducing the lixiviant into the reaction vessel at a firstflow rate, wherein the pregnant leach solution is extracted from thereaction vessel at a second flow rate, and wherein the first and secondflow rates are simultaneous.
 39. The method of claim 38, wherein thefirst and second flow rates are essentially equal, essentially constant,or essentially equal and constant.
 40. The method of claim 31, andfurther comprising introducing the crushed ore into the reaction vesselat a first flow rate, wherein the post-reaction solids are extractedfrom the reaction vessel at a second flow rate, and wherein the firstand second flow rates are simultaneous.
 41. The method of claim 40,wherein the first and second flow rates are essentially equal,essentially constant, or essentially equal and constant.
 42. The methodof claim 31, and further comprising separating at least twopredetermined sizes of solids from at least some of the post-reactionsolids.
 43. The method of claim 31, and further comprising removingpregnant leach solution from at least some of the post-reaction solids,wherein the removing the pregnant leach solution includes at least oneof: centrifuging at least some of the post-reaction solids; passing atleast some of the post-reaction solids through a filter; passing atleast some of the post-reaction solids along a screen; or leaching atleast some of the post-reaction solids in barren solution wash, thusderiving an aqueous leachate.
 44. The method of claim 31, and furthercomprising separating at least one dissolved material out of thepregnant leach solution, wherein the at least one dissolved materialincludes gold, silver, a platinum group metal, gallium, germanium,copper, zinc, uranium, cobalt, molybdenum, nickel, lead, a refractorymetal, a light metal, crude oil, caregens, or a rare earth element. 45.The method of claim 31, and further comprising controlling at least oneof temperature, pH, Eh, a gas concentration, or liquid concentration,within the reaction vessel during the reacting the crushed ore with thelixiviant.